py有关函数与字典的问题

Question

article = '''This is a photograph of our village.
Our village is in a valley.
It is between two hills.
The village is on a river.
Here is another photograph of the village.
My wife and I are walking along the banks of the river.
We are on the left.
There is a boy in the water.
He is swimming across the river.
Here is another photograph.
This is the school building.
It is beside a park.
The park is on the right.
Some children are coming out of the building.
Some of them are going into the park.
'''
def get_word_count(article):
  count = {}
  word_list=article.lower().replace('.','').split()
  for word in word_list:
    if word in count:
      count[word] += 1
    else:
      count[word] = 1
  return count
print(get_word_count(article))

为啥定义的空字典但是在执行if语句时字典中已经有了内容呢？

各位大神求解！！！

Answer 1

   else:中不就是   count[word] = 1 对字典添加属性了么

 

    if word in count:

      count[word] += 1

    else:

      count[word] = 1

这个if---else的意思就是：

如果 word的值 在 count字典中，

则count字典的word值的属性增加1

否则就给 count字典中添加一个word值的属性并赋值为1。

 

if---else是在for循环中重复执行的。

当某个word值第一次出现时是，给字典中添加一个属性。

当这个word值再次出现时，字典中就已经有了这个属性，就对这个属性增加1。